Fosi Audio V3 Mono Amplifier Review

[Xenio]

3e Audio A5, A7 and A7 Mono are 2 ohm stable, A5se and A7se only go up to 4 ohm.

That's great thanks, but they are not just power amplifier, at first I dismissed them because they were not just power amplifier, and it still bothers me having a useless knob, but after taking a deeper look there is a bypass volume to disable pre-amp which is great.
No 12v trigger like NC502MP offering, but both Fosi and 3e Audio supports automatic detection through input voltage right ?

Any one of those TPA3255 will be enough to drive annoying 2.5 Ohms speakers without any reliability and stability issue ?

 

[Roland68]

That's great thanks, but they are not just power amplifier, at first I dismissed them because they were not just power amplifier, and it still bothers me having a useless knob, but after taking a deeper look there is a bypass volume to disable pre-amp which is great.
No 12v trigger like NC502MP offering, but both Fosi and 3e Audio supports automatic detection through input voltage right ?

Any one of those TPA3255 will be enough to drive annoying 2.5 Ohms speakers without any reliability and stability issue ?

I can't comment on the automatic detection.
No one can guarantee that a 2-ohm stable amplifier will work with your speakers, regardless of the manufacturer. But I know a few people who use 3e Audio amplifiers with TPA3255 in PBTL mode with very impedance-critical speakers without any problems.

 

[Xenio]

Why can no one guarantee that if the amp is stable at 30V under 2 Ohms (on one channel due to PSU limit) according to the review ?

They have 92.5dB/2.83V/m, I listen at 2.5m, I don't need that much power (i guess), just 2.5 Ohms stability.

 

[Roland68]

Why can no one guarantee that if the amp is stable at 30V under 2 Ohms (on one channel due to PSU limit) according to the review ?

They have 92.5dB/2.83V/m, I listen at 2.5m, I don't need that much power (i guess), just 2.5 Ohms stability.

The amplifier's stability at 2 ohms can be guaranteed with certainty, but only with a dummy load. Any amplifier stated to be stable at 2 ohms should also have passed the test with a 2 ohm resistor.

But a loudspeaker is not a resistor; it's a complex structure. No one knows how your loudspeakers actually behave, how the crossover is constructed, or whether your loudspeaker is behaving in an "unnatural" way. I've had enough critical loudspeakers in my hands, so I'm pointing this out to you.

 

[Xenio]

I see

Well I hope it will be enough, I just bought the 3e audio A7

 

[rsqt]

You mean 2Ohms DC resistance. If you have a 3 Way passive speaker with Bassreflex you have for example in the lower frequencies where the most power is needed only a very small "2Ohm -region" while listening to music.
I have several subs on the V3 with 1,8Ohm DC resistance alltogether and it works. Just have an eye on the temperature or add some cooling.

 

[Xenio]

I bought the 3e audio A7 due to not being sure about reliability with the Fosi, and also it doesn't have 3 boxes which is cool

I'll have a crossover before that will splits lower frequencies only towards the subs
But the speakers have 3 woofers and a tweeter (and bass reflex yes), focal aria 948. I'm getting them for 1300eur.
They are around 2.5 Ohms between 100-800Hz ~~

I'll check temps yeah thanks

 

[saberger0357]

I’ve had these only for a few days and am incredibly impressed. I’ve had them on mostly my 4 ohm AR3’s and 8 ohm JBL L100t3’s and they make both those vintage, classic speakers sing as beautifully as my several vintage McIntosh amps do.

I’ve read all the glowing reports about the 3e Audio A7 and have been intrigued to say the least. But solely by comparing the reviews and Amir’s numbers I’m having a difficult time understanding, given the similarity in ratings, why the A7’s are considerably more expensive. A pair without psu are $440, while a pair of the V3 Mono’s with psu are less then $300.

What am I missing?

 

[SoySalsaPicante]

I’ve had these only for a few days and am incredibly impressed. I’ve had them on mostly my 4 ohm AR3’s and 8 ohm JBL L100t3’s and they make both those vintage, classic speakers sing as beautifully as my several vintage McIntosh amps do.

I’ve read all the glowing reports about the 3e Audio A7 and have been intrigued to say the least but solely by comparing the reviews and Amir’s numbers I’m having a difficult time understanding given the similarity in ratings why the A7’s are considerably more expensive. A pair without psu are $440, while a pair of the V3 Mono’s with psu are less then $300.

What am I missing?

I believe there are some who believe a pair of A7 Mono will provide better thermal management than a pair of V3 Mono.

I do not know if there is a consensus on how thermal management of a single A7 (stereo) compares to a pair of V3 Mono.

 

[saberger0357]

I believe there are some who believe a pair of A7 Mono will provide better thermal management than a pair of V3 Mono.

I do not know if there is a consensus on how thermal management of a single A7 (stereo) compares to a pair of V3 Mono.

As in how warm they get? The V3’s get warm but not ever what I would get concerning. Certainly not to the point of wanting to spend an additional $100+ on an other very similar rated amp.

 

[Roland68]

I’ve had these only for a few days and am incredibly impressed. I’ve had them on mostly my 4 ohm AR3’s and 8 ohm JBL L100t3’s and they make both those vintage, classic speakers sing as beautifully as my several vintage McIntosh amps do.

I’ve read all the glowing reports about the 3e Audio A7 and have been intrigued to say the least but solely by comparing the reviews and Amir’s numbers I’m having a difficult time understanding given the similarity in ratings why the A7’s are considerably more expensive. A pair without psu are $440, while a pair of the V3 Mono’s with psu are less then $300.

What am I missing?

3E Audio has significantly more experience with TPA325x amplifiers, especially with the implementation of PFFB.
- An A7 Stereo has slightly more power than two V3 Monos
- Slightly better SINAD
- Noise levels generally seem to be somewhat lower
- In contrast to the V3 Mono, the A7 can truly be classified as load-independent
- The performance and stability at 2 ohms is impressive
- If 2 ohm stability isn't required, the A7se is cheaper with almost the same power

None of this makes the V3 Mono a worse amplifier, and the price/performance ratio is incredibly good.

But the last 1-3% have always been more expensive than the first 97%. In this respect, both the performance and the price/performance ratio of the 3E Audio Ax series are unbeatable. Amplifiers with at least these measured values, this high performance, and the price can be counted on one hand. If one of these aspects isn't important, the selection becomes significantly larger.

 

[saberger0357]

3E Audio has significantly more experience with TPA325x amplifiers, especially with the implementation of PFFB.
- An A7 Stereo has slightly more power than two V3 Monos
- Slightly better SINAD
- Noise levels generally seem to be somewhat lower
- In contrast to the V3 Mono, the A7 can truly be classified as load-independent
- The performance and stability at 2 ohms is impressive
- If 2 ohm stability isn't required, the A7se is cheaper with almost the same power

None of this makes the V3 Mono a worse amplifier, and the price/performance ratio is incredibly good.

But the last 1-3% have always been more expensive than the first 97%. In this respect, both the performance and the price/performance ratio of the 3E Audio Ax series are unbeatable. Amplifiers with at least these measured values, this high performance, and the price can be counted on one hand. If one of these aspects isn't important, the selection becomes significantly larger.

Thanks. All of these points are very much worthy of consideration. And as I look at your outline, it would seem both amps are very, very close. My understanding is that the V3 Mono utilizes PFFB technology just like the A7 and therefore is also load independent, but not having gone through the entire review thread perhaps I'm missing some important details. Similarly, the V3 Mono review indicates it too provides excellent performance and stability at 2 ohms.

Again, this is not to at all to dismiss the impressiveness of the A7. I'm very curious and would love to have the opportunity to compare. But the A7 still doesn't seem to me to be so far ahead of the V3 Mono to warrant the extra $150.

Nice to have choices of such excellence at prices that should satisfy almost every budget.

 

[Roland68]

Thanks. All of these points are very much worthy of consideration. And as I do consider, and look at your outline, it would seem both amps are very, very close. My understanding is that the V3 Mono utilizes PFFB technology just like the A7 and therefore is also load independent, but not having gone the entire review thread perhaps I'm missing some important details. Similarly, the V3 Mono review indicates it too provides excellent performance and stability at 2 ohms.

Again, this is not to at all dismiss the impressiveness of the A7, and I'm very curious and would love to have the opportunity to compare. But the A7 still doesn't seem to me to be so far ahead of the V3 Mono to warrant the extra $150.

Nice to have choices of such excellence at prices that should satisfy almost every budget.

That's exactly what I was trying to say: it's always a matter of priorities and price/performance.
Many people are perfectly happy with a Fosi V3 Stereo for around €110 (48V power supply), and honestly, the air above that is very thin. If I had to limit myself, it would be more than enough.

 

[saberger0357]

That's exactly what I was trying to say: it's always a matter of priorities and price/performance.
Many people are perfectly happy with a Fosi V3 Stereo for around €110 (48V power supply), and honestly, the air above that is very thin. If I had to limit myself, it would be more than enough.

Agree 100%.

Thanks again.

 

[telemike]

The V3 monos have been sounding great drivng my Klipsch Forter IV and if it had been out at the time I bought them, I would have bought Wiim VIbelink to match my Wiim Ultra.

 

[Oldson]

bagged a used pair of the V3 mono's.
would i likely notice any benefits from using balanced input over se from my RME dac?

 

[SMen]

bagged a used pair of the V3 mono's.
would i likely notice any benefits from using balanced input over se from my RME dac?

You will have to let us know ;-) ... I use the balanced, but I work around a carefully sought out balanced volume control ... and there are many instances where it won't make a difference. Might depend more on your (what looks like) an excellent dac (and / or set up regarding interconnect lengths etc.)

 

[Oldson]

You will have to let us know ;-) ... I use the balanced, but I work around a carefully sought out balanced volume control ... and there are many instances where it won't make a difference. Might depend more on your (what looks like) an excellent dac (and / or set up regarding interconnect lengths etc.)

i dont have any balanced cables, so i cant try for myself.
if there is no benefit i will leave as it is

 

[Brian Hall]

i dont have any balanced cables, so i cant try for myself.
if there is no benefit i will leave as it is

If you don't have any ground noise issues from the cables you have, there is no benefit to changing. There is a switch on the V3 Monos for gain on the back of each. Just make sure to set that according to your input source.

I tried both balanced and RCA cables from a DMP-A6 with the V3 monos and there was no noticeable difference driving Klipsch Heresy IVs.

 

[Oldson]

If you don't have any ground noise issues from the cables you have, there is no benefit to changing. There is a switch on the V3 Monos for gain on the back of each. Just make sure to set that according to your input source.

I tried both balanced and RCA cables from a DMP-A6 with the V3 monos and there was no noticeable difference driving Klipsch Heresy IVs.

thanks Brian , i will stick with rca.